<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>for循环画三角形</title>
    <style>
        span{
            color: white;
        }
    </style>
</head>
<body>
    <script>
        for(let i = 0; i < 5; i++){
            for (let j = 0; j <= i; j++) {
                document.write(`<span>^</span>`);
            }
            for (let m = 0; m < (2*i+1); m++) {
                document.write("*");
                
            }
            document.write(`<br>`);
        }
    </script>
</body>
</html>